The mouse is just working perfectly, mouSTer both, and internally on the C64U, and in 2Mhz mode it looks *very* smooth, and on this you can crank it up to a lot more. It literally plays identical to the DOS release, astonishing work, really! Yes, the doors (including "secret doors" (they are visible here) are locked in this speed though, and one more thing: the machine gun shoots the ammo way, way faster. You're empty almost instantly on max Mhz.